By way of introduction, it is well-known that wireless local area networks, also known as WLAN, are a flexible wireless communications system that is widely used as an alternative to wired local area networks, or as an extension of the same. They use radio frequency technologies that enable greater user mobility by minimizing wired connections. These networks have become increasingly important in a number of fields, such as warehouses or manufacturing, wherein information is transmitted in real time to a central terminal. They are also very popular in homes for sharing Internet access between various computers.
In a typical wireless LAN configuration, the access points (AP) connect the fixed location wired network by means of standard wiring. The access point (AP) receives the information, stores it, and transmits it between the WLAN and the wired LAN. One single access point can support a small group of users, and can function with a reach of at least thirty meters, and up to several hundred meters.
In general, WLAN networks operate using the IEEE 802.11 protocols.
The use of WLAN networks is spreading further and further, taking on large-scale facilities, which can comprise several hundred access points. These extensive networks tend to respond to usages involving high user density.
The main problem with WLAN networks is that, since they use radio transmission, interference occurs between the clients and the access points. The number of radio channels is very limited, and the requirement of providing service to a high number of users implies having to re-use the channels in more than one access point. This increases the number of instances of interference, as well as the level of electromagnetic noise in the environment.
Furthermore, each access point has a fixed configuration, which makes it hard to expand the networks, as adding a new access point to the network has consequences for the configuration of each existing access point in the network.
As for the state of the art and its development through time, Wi-Fi systems were originally autonomous. Each access point had the full ability to create its cell, and manage both the clients associated with the same and the communications between them, and between these clients and the wired network.
When Wi-Fi networks ceased to be an one-time solution for solving specific, small-scale problems, and became large and complex systems supporting a significant portion of companies' communications, or, in some cases, became a source of income in and of themselves (as in the case of airport hot-spots), the need arose to have centralized management systems.
The emergence of these systems was brought about by the high cost of access points in their early days. To bring down the cost of these large systems, it was decided that the access points should be made less intelligent, and this intelligence was then transferred to a centralized system. It is true that the cost of this control system is usually high, but if the system is large, the reduction in the price of each access point makes up for this fact, and the overall price is lower than if the system were made with autonomous access points.
Over time, Wi-Fi networks gradually became able to support more services, and more and more was demanded of them, as more features and configuration options had to be provided in order to make them suitable for the applications and services that made use of them. In systems with a high number of access points, the manual configuration and maintenance of each one of them, along with error detection and correction thereof, became too complex, and the cost in terms of time and personnel became too high.
The aim of centralized management systems is to alleviate these problems and offer added features. While it is true that it is not possible to list all the features of these systems, as there is no single model and each manufacturer adopts the approach it deems best, still, they tend to have some basic characteristics and features in common.
Normally, the controller is sold as a closed, independent system, but inside it is always a computer with associated and pre-installed software, to which the user does not have access, except through the configuration console. In any case, the controllers are connected to the client's Ethernet connection, from which they detect the access points with which it is compatible. Once detected, it carries out a prior configuration of the same, and will enable them to be centrally managed from one single point, the controller.
Depending on the manufacturer, different measures are implemented to choose which access points are to be managed, either through preconfiguration of the IP address at the access point, or through some type of filter and key in the controller. Once the access point has been added, a base configuration is automatically defined for it, which reduces installation times and minimizes configuration errors.
There is a trend towards a context, then, for the installation of new systems to be simplified so that, in addition, after its initial deployment, the controller makes it possible to configure the various access points from a single console, individually, in groups, or globally, as well as receive alarms concerning their operations.
As mentioned, their features depend on each manufacturer, but these are a few of the ones that are offered:                Centralized management: One single console for managing the various access points.        Centralization of events: In broad systems, with a high number of access points, it is not feasible to access each one to learn of the events that have taken place, and then connect the data obtained from each one of them. The controller makes it possible to automate this process, saving on costs and increasing the reliability of the network.        Heightened and centralized security: Makes it possible to manage the admission of Wi-Fi clients, define profiles, grant clients access to different parts of the network or to services based on their identity, filters, and access detection.        
At present, there are various manufacturers who have designed their own exclusive protocols for managing the control of their own wireless networks based on standard IEEE 802.11. One of the most widespread has been LWAPP (Lightweight Access Point Protocol). This network protocol is used to centrally manage several access points in a WLAN wireless network. There are two layer modes, the already obsolete Layer 2 mode, and Layer 3 mode, which are found by default in most devices.
Initially developed by Airespace and NTT DoCoMo, and eventually approved as a standard by the IETF (Internet Engineering Task Force) in RFC 5412, the aims of this protocol are:                To use the simplest and cheapest access points possible. As many tasks are removed as possible.        To centralize filtering, QoS, authentification and encryption tasks in one centralized device.        To provide a vendor-independent encapsulation and transport mechanism.        
CAPWAP (Control and Provisioning of Wireless Access Points) is a standard that emerged out of LWAPP. The specifications of the protocol are described in RFC 5415, and in RFC 5416 a binding to standard 802.11 is provided.
The state machine of CAPWAP is similar to that of LWAPP, but with the addition of the establishment of a DTLS (Datagram Transport Layer Security) tunnel. The standard provides configuration management and device management, allowing for configurations and firmware to be loaded onto the access points from the controller.
This protocol differentiates between data traffic and control traffic, as LWAPP does. However, only the control messages are transmitted by means of a DTLS tunnel. Both the access points and controllers must be preconfigured in order to associate with each other. Both the AP and the controller must be loaded with either PSKs or certificate files to enable encrypted communication.
Subsequently, the trend on the market has been to simplify the access points by centralizing the management logic in one single device. This decision is based on the fact that when deploying wireless networks in areas with high user density, the number of access points grows considerably. However, at present there are a number of embedded SoC (Systems on a Chip) alternatives, based on ARM architecture, that enable high data processing capacity at a low cost. This makes it possible to make the access points more complex with practically no impact on cost.
To conclude, the present invention provides, vis-à-vis the state of the art, a decentralized control technology for wireless networks, which distributes the control logic between all of the access points that make up the network, eliminating the centralized controller from the network architecture by means of communication between the access points themselves, which ensures efficient management of the resources of the wireless network.
The advantages that this architecture provides are the following:                Because it is decentralized, it is not dependent on any particular element, as all of the access points behave like small controllers that are able to interoperate with each other.        Each node behaves like a controller and provides support to the adjacent nodes.        The network tasks are thus distributed, without overloading any one element, thus preventing bottlenecks.        It reduces the high hardware costs of the centralized controller.        It is 100% scalable, making it possible to add more access points without having to increase the capabilities of the centralized controller.        It enables management from any point with network access.        Redundancy to failures, as the logic of the controller and, as such, the operations of the network is not compromised by the failure of any one access point.        Automatic configuration of the transmit power of the access points belonging to the network in order to reduce unnecessary interference.        Automatic configuration of the channel used by each access point belonging to the network in order to reduce interference between access points and increase the number of simultaneous transmissions in a limited physical environment.        Automatic selection of the access point that provides service to a new station or user (STA, “Station”), in order to reduce interference between access points and stations operating on the same channel or on different channels.        Balance the network load with the aim of reducing interference within the network and the number of hidden nodes, as well as taking advantage of the total transmission capacity of the network to prevent bottlenecks from arising in some access points while others remain idle.        Exclusion of users based on location, denying service to users who are located outside the range of operation of the network when these users receive the signal of the network.        